1D Shaker

RPI’s large 1D shaker is a servo-hydraulically controlled system designed to produce 1D (horizontal) shaking in response to an applied input voltage signal. It is designed for use with medium-sized (or larger) geotechnical centrifuges, for studies in which application of input motions to the base of a model container is desired. Maximum design shaking force is 16,000 lbf at a supply pressure of 3,000 psi, the maximum stroke (i.e., peak-to-peak displacement of the slip-table) is 1.25 inches. The nominal operating frequency range is 20-600 Hz.

The shaking force is developed within the hydraulic actuators and is applied between the actuators, which are fixed to the platform of the centrifuge, and the slip-table, to which the model container is attached. Feedback signals are derived from:

the position of the slip-table

the internal state of the servovalves

the force (pressure) developed by each actuator

These signals are compared to the applied input signal within the servocontroller to produce an actuating or error signal. This error signal is amplified (Team model 1528 power amplifiers) and the resulting high current used to drive the voice coils in the pilot stage servovalves (Team model V-20). A second, high flow slave-stage valve (Team model V-750) acts as a hydraulic amplifier, converting the tiny flow produced by the V-20 valve into the large flows needed to supply the actuators.

Performance Specifications

Method

Servo-hydraulic multi-actuator system

Shaking Type

Periodic or random, determined by input signal

Shaking Direction

One prototype horizontal direction

Force

16,000 Lbf (71 kN)

Max. shaking velocity

45 in/sec (1.1 m/s)

Peak Table Displacement

0.625 in (15.9 mm)

Max. Payload Dimensions
(L × W × H)

38 in × 26 in × 28 in
(965 mm × 660 mm × 711 mm)

Max. Payload Weight

550 pounds (250 kg)

Frequency Range

20–600 Hz

Max. Centrifugal Acceleration

100 g

Stroke

1.25″ peak to peak (31.75 mm)

This work was supported by the George E. Brown, Jr. Network for Earthquake Engineering Simulation (NEES) Program of the National Science Foundation under Award Number CMMI-0927178.